Patent Application
20120038157
1. Field of the Invention
A synchronous induced wind power generation system is provided, which is comprised of a direct-coupled turbine-generator section on a horizontally rotatable gimbal that allows it to wind-vane into the prevailing wind. In particular, a wind powered synchronous electrical generation system is provided having a turbine-generator section with a horizontally disposed rotating shaft therein connecting the turbine to the generator, air inlet and air discharge shrouds formed thereon so as to induce higher differential air pressure across the turbine, turbine brakes and adjustable pitch directrix blading to control the rotational speed of the turbine and the shaft power delivered to the synchronous generator, and a control system operable to control the turbine brakes, directrix blading pitch and the synchronous generator.
2. Description of the Related Art
Wind as an alternate motive force for generating electricity has long provided an attractive alternative to conventional power generation techniques. However, the effectiveness of conventional wind power generation systems have been limited by various difficulties such as, for example, the inconsistency of the wind, appropriate locations for placement of wind power generation system far from load centers and the problems of long distance transmission of power, difficulty in repair and maintenance of large systems, etc. These difficulties have inhibited large scale adoption of wind power as an alternate means of energy.
With regards to appropriate locations to place the systems, generally, wind power systems using turbines are developed, built and installed by large power companies, and are generally large units with very long turbine blades. The generator is mounted within a housing or nacelle that is positioned on top of a truss or tubular tower. The turbine blades transform wind energy into a rotational force or torque that drives a generator through a gearbox that steps the speed of the generator up to around 1200 RPM. The generator is usually a DC generator, and produces DC power in proportion to a variable wind speed. The DC power is run through an inverter to get AC power, and the AC power is delivered to the power grid for sale.
The power companies that install such wind turbines are generally interested in systems capable of generating large amounts of power. Thus, most current wind turbines use large-sized blades (e.g., 60 meters or more in length). These large size blades result in an economy of scale. However, the longer blades require a supporting tower having a corresponding increased height and size.
Further, such large size blades prevent placement of conventional wind turbines within urban/suburban environments where the greatest demand for energy exists. Moreover, the large wind turbines are more subject to damage from high winds, as well as structural fatigue failures. Namely, the blades are subject to fatigue by encountering significantly higher wind loads at the top of the arc of rotation, followed a second later by lower velocity wind loads, which culminate at the bottom of the arc of rotation as the blade passes the supporting column, where the flow of air is disrupted.
To minimize the chance that such conventional wind turbines are damaged by high winds, conventional wind turbines are shut down when winds exceed a predetermined speed. And, the large blades with high tip velocities sometimes strike birds, resulting in conflict with environmental groups.
In view of the deficiencies of conventional wind turbines discussed above, it is an object of the present invention to provide a wind driven electricity generating system that can be run safely at 100% load regardless of higher wind speeds, that results in distributed power generation by use of many small wind generators inside load centers, that do not strike birds, that have no problem with blade failures, and that directly generate synchronous AC power (no inverter needed), thus replacing retail power.
It is a further object of the present invention to provide a wind driven electricity generating system that is structurally unobtrusive so as to be installable in urban/suburban environments close to or at the source of power consumption, thereby negating the need for expensive and inefficient power transmission lines.
In order to achieve the objects of the present invention, the present inventors endeavored to develop a synchronous induced wind powered generation system capable of generating synchronous and consistent AC power regardless of high wind velocity or direction, and which may be installed in various locations, including urban and suburban environments. Accordingly, in a first embodiment of the present invention, a synchronous induced wind power generation system is provided comprising:
(a) a turbine-generator section comprised of an outer shell having a first end, a second end opposite the first end, an interior area disposed there between, an air inlet shroud disposed at the first end, an air discharge shroud disposed at the second end, a horizontal wind flow axis extending from the air inlet shroud to the air discharge shroud, and a vertical axis of rotation disposed perpendicular to the wind flow axis;
(b) one or more turbine/generator units disposed within the interior area of the turbine-generator section at or between the air inlet shroud and air discharge shroud, each of said turbine/generator units comprised of:
(c) a control system in conductive communication with each synchronous generator operable to synchronize the frequency, phase and voltage of the synchronous generator with the frequency, phase and voltage of an external AC power line in conductive communication with the synchronous generator, and in conductive or mechanical communication with the turbine magnetic brakes and adjustable pitch directrix bladinges so as to be operable to control the speed of rotation with no load, or maximum torque during synchronous operation of the turbine, thereby controlling shaft power delivered to the generator, said control system comprised of:
The permanent magnets are preferably capable of providing braking power equivalent to the maximum rated wind speed of the system, such that with the permanent magnets in place, the system will not be damaged by winds up to the maximum wind rating with the generator off line and unattended. Further, the turbine-generator section aligns itself with the prevailing wind direction by wind vane action, with rotation about a pivot on a central pedestal, and is preferably supported by wheels on a circular track that surrounds the entire device.
The pitch of the directrix blading is preferably capable of being adjusted to both increase or decrease the torque output of the turbine, and in the case of severely high wind speeds, to reduce the turbine torque to near zero when needed, thus allowing wind to pass through the turbine without taking much energy from it when the unit is disconnected from the load. The pitch of the adjustable directrix blades may be constantly adjusted to maintain peak efficiency of the turbine as the prevailing wind speed changes.
In a preferred embodiment, the synchronous induced wind power generation of the first embodiment above is provided, wherein the interior area of the turbine-generator section between the air inlet shroud and the air discharge shroud is smaller than the areas of the air inlet and air discharge shrouds at their largest (anterior) areas, whereby the air inlet shroud funnels air into the turbine-generator section, and the air discharge shroud induces a negative air pressure, thereby creating an induced differential pressure across the wind turbine. Further, preferably, the air discharge shroud has a larger discharge area than the air inlet shroud, which may serve to aid the wind vane effect that aids in keeping the air inlet shroud pointed into the prevailing wind.
More preferably, the anterior area of the air discharge shroud is 1.1 to 16 times larger than the interior area of the turbine-generator section. Further, the anterior area of the air discharge shroud is 8 to 13 times larger than the interior area of the turbine-generator section. Most preferably, the anterior area of the air discharge shroud is about 12 times larger than the interior area of the turbine-generator section. In each preferred embodiment, the area of the air inlet shroud at its largest (anterior) area is smaller than the area of the air discharge shroud at its anterior area, and the anterior area size ratio between the air inlet and air discharge shrouds is adjusted to optimize the air differential pressure.
In a further preferred embodiment, the synchronous induced wind power generation system of the first embodiment above is provided, further comprising a computer program product (computer software application) for managing operation of the wind power generation system. This computer program product is comprised of computer usable program code operable to enable the computer processor to communicate with one or more of the various sensors, to synchronize frequency and voltage phase of the generator units with the external power line in communication with the system, and to control operation of the turbine magnetic brakes and the pitch of the adjustable pitch directrix blades so as to limit the maximum power delivered to the generator during both high wind conditions and during wind gusts. This functionality is achieved via the removably disposed permanent magnets which act to limit shaft power to the turbine, that can be deployed during high wind conditions and during loss of load conditions via the electromagnets operable to achieve the rapid response times required to handle wind gusts, and via varying of the pitch of the adjustable pitch directrix blades so as to adjust the range of torque that the turbine can deliver to the generator.
Further, the computer usable program code is operable to control the turbine magnetic brakes and the pitch of the adjustable pitch directrix blades so as to control and monitor the speed of rotation of the turbine, especially during initial synchronization with the power line and during loss of load, when the load is suddenly removed and the magnetic brakes must supply braking action equivalent to 100% of the generator's output at the instant that the load is lost and attempt to maintain the phase of the line in case the load returns a few seconds later.
Further, the computer usable program code is operable to control the status of the 3-phase AC power switch (breaker) between the generator and the external power line, the field current of the synchronous generator to control VAR (volt-amps reactive) generation during normal operation, and the interruption of field current immediately before opening the breaker, especially when instantaneous overcurrent is detected and an immediate shutdown is required.
In another preferred embodiment, the synchronous induced wind power generation system of the first embodiment above is provided, further comprising one or more controllable, pivotable air bypass (relief) doors disposed in the air discharge shroud, which may open as needed to allow air to freely pass through areas of the air discharge shroud, so as to limit the stress on the entire structure and reduce the differential air pressure across the turbine-generator unit during high wind conditions. Preferably, these air bypass doors open inward, into the interior volume of the air discharge shroud.
Additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The aspects of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
As illustrated in
Further, the low noise level produced by the system 1 of the present invention during operation thereof is unobtrusive to occupants and neighbors. The electrical load of the building below can be partially met by the system of the present invention by converting the otherwise unused wind energy flowing across the roof into electrical power. Further, using the existing building as a site for this invention negates the cost of building any high structure to take advantage of the higher wind speeds at greater heights above ground level.
In particular, as shown in
Specifically, as shown in
In a preferred embodiment, as illustrated in
The anterior area of the air inlet shroud 13 is preferably smaller than the anterior area of the air discharge shroud 15. This configuration enables the creation of induced differential air pressure, which allows the system 1 to begin to produce meaningful power at lower ambient air speeds than conventional wind power generators.
By forming the turbine-generator section with an air discharge shroud 15 having a larger anterior area than the interior area 11 of the turbine-generator section 3, and an air inlet shroud with an anterior area larger than the interior area 11 of the turbine-generator section 3, a pair of coaxial “funnels” are formed. Thus, wind that is blowing horizontal to the ground can blow through one end of the turbine-generator section 3 and exit out the other end. The exit end (air discharge shroud 15) induces a negative pressure from the wind blowing past it. The upwind end (air inlet shroud 13) forms a positive pressure from the wind against it. The differential pressure between the two shrouds 13, 15 causes a substantial increase in wind velocity through the interior area 11 of the turbine-generator section 3, and hence an increased wind velocity over the turbine blades 23 disposed therein. The shrouding, rather than a bare turbine without shrouding, is preferred so as to allow for a small, high speed turbine that is directly coupled to a generator without losing the ability to arrest large amounts of energy from the passing wind.
Specifically, as shown in
As illustrated in FIGS. 4 and 6-8, one or more turbine brakes are disposed on or adjacent to the turbine blades 23. The turbine brakes, which are in communication with the control system 33 so as be operated thereby, are comprised of metallic brake rotor(s) 55 and turbine brake permanent magnets 56 or electromagnets 49 contained in housing 52. As illustrated in
In addition, preferably, the turbine brakes comprise permanent magnets 56, which are movably disposed adjacent the metallic brake rotor(s) 55. For example, a pivot mechanism 54 may be utilized to move the permanent magnet within a distance operable to induce magnetic forces on the magnetic brake rotor. The permanent magnets 56, as illustrated in
The magnetic brakes allow precise control of the turbine torque delivered to the generator, as well as control of turbine rotational speed when the turbine-generator unit 21 is off-line. Further, the magnetic turbine brakes, which are in conductive or mechanical communication with the control system 33, are used to control the speed and phase of rotation during start-up synchronization, the maximum speed of rotation of the turbine blades 23 with no load, and the torque delivered to the generator during synchronous operation of the turbine generator unit 21, thereby controlling or limiting shaft power delivered to the synchronous generator 31.
Further, as illustrated in
For example, as illustrated in
As wind speed further increases, the pitch of the adjustable pitch directrix blading 67 is decreased, thus redirecting the flow of incoming air in a direction less correspondent to the rotation of the turbine blades 23, thereby limiting turbine power to around 125%. As wind speed further increases, the pitch of the adjustable pitch directrix blading 67 can be adjusted to turn the inlet air in the opposite direction of rotation of the turbine blades 23, as illustrated in
The permanent magnets 56 are also deployed (moved within magnetic range of the magnetic brake rotors 55) as needed to shed wind power in higher winds, and to keep the electrical generation from exceeding 100% power output. To limit the stress on the structure during higher wind speeds, the pivotable air bypass doors 53, which are in communication with the control system 33, open inwardly into the interior area of the air discharge shroud 15 as needed, as illustrated in
As mentioned above, and as illustrated in
The ability to choose a generator to match the speed of the turbine desirably allows for direct drive, rather than a geared drive, thereby simplifying the design and minimizing the cost of construction. The turbine is designed to optimize energy transfer at the synchronous speed of the generator. The synchronous generator 31 runs synchronized with the power line when operating, and generates 60 hertz AC power (for US applications) at any power factor desired, such that the AC output voltage can be regulated by controlling the field current of the generator. Thus, the synchronous generator 31 of the present invention can produce VARS to create any Power Factor within the operating range of the generator.
During start-up, the magnetic brakes are used to absorb all turbine power until some predetermined minimum power level (perhaps 5%) is achieved, while holding the turbine speed at approximately the synchronous speed of the generator. This is preferably achieved by inserting/providing a sufficient amount of permanent magnets 56 to allow turbine speed to reach synchronous speed while absorbing enough energy to equal some predetermined minimum power level of the generator's power rating. Thus, when the turbine speed reaches synchronous speed and that minimum power level has been achieved, and the unit can be brought on line. At that point, the electromagnets are activated as the permanent magnets are removed (i.e. moved to a location wherein no magnetic force is exerted on the magnetic brake rotors), and the braking is adjusted until the turbine is running at synchronous speed. Then, the exciter, an electromagnet that produces the magnetic field that rotates inside the stator of the generator, is energized so as to cause AC voltage output of the generator to match the voltage of the external electrical power grid.
The magnetic brakes are used to adjust the phase of the generator to match the phase of the external electrical power grid, then the unit breaker 41 is closed to connect the synchronous generator 31 to the external electrical power grid. The magnetic brakes are then released, allowing the power that was being absorbed by the magnetic brakes to reach the generator. If the generator power falls below about 1%, the unit breaker 41 is opened and the magnetic brakes resume controlling the maximum speed of the turbine.
The control system 33 is comprised of a computer processor 35. The computer processor 35 may be any conventional computer, such as a desktop computer, a laptop computer, or any computing mechanism that performs operations via a microprocessor, which is a programmable digital electronic component that incorporates the functions of a central processing unit (CPU) on a single semi-conducting integrated circuit (IC). One or more microprocessors typically serve as the CPU in a computer system, embedded system, or handheld device.
A data processing system suitable for storing and/or executing program code includes at least one processor coupled directly or indirectly to memory elements through a system bus. The memory elements can include local memory employed during actual execution of the program code, bulk storage, and cache memories which provide temporary storage of at least some program code in order to reduce the number of times code must be retrieved from bulk storage during execution. Input/output or I/O devices (including but not limited to keyboards, displays, pointing devices, etc.) can be coupled to the system either directly or through intervening I/O controllers. Network adapters may also be coupled to the system to enable the data processing system to become coupled to other data processing systems or remote printers or storage devices through intervening private or public networks. Modems, cable modem and Ethernet cards are just a few of the currently available types of network adapters.
The control system 33 is further comprised of one or more of a phase sensor 37 and speed sensor 38, both of which are in connection with the computer processor 35 and each of the synchronous generators 31. The phase sensor 37 and speed sensor 38 are preferably one or more of a voltage sensor, an optical sensor, a mechanical sensor, or a magnetic sensor. Further, a turbine brake electromagnets and permanent magnets controller 57 is in communication with the computer processor 35, said turbine brake electromagnets and permanent magnets controller operable to control the application of magnetic breaking force upon the turbine blades 23. In addition, in a preferred embodiment, one or more differential pressure sensors 65 are provided in communication with the computer processor 35 to determine the wind power of the turbine at all times. The wind power of the turbine is the sum of the power delivered to the generator plus the power absorbed by the magnetic brakes.
The phase sensor(s) 37 are operable to sense the electrical phase of the generator with respect to the external AC line as well as turbine-generator speed prior to connection with the external AC line. The speed sensor 38 measures the rotational speed of the turbine-generator assembly. Data is recorded by each of these sensors/detectors, and fed to the computer processor 35 for use/analysis by the control system 33 in determining proper operating parameters of the system 1. In addition, as mentioned above, the control system further comprises a servo controller 69, as shown in
In a further preferred embodiment, as illustrated in
The synchronous induced wind power generation system 1 of the present invention further comprises a computer program product for managing operation of the wind power generation system, and method of operating the wind power generation system via use of same. The computer program product is stored on a computer-usable or computer readable medium which may be any apparatus that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The medium can be an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium. Examples of a computer-readable medium include a semiconductor or solid state memory, a removable FLASH memory medium, a random access memory (RAM), a read-only memory (ROM), a rigid magnetic disk and an optical 16 disk. Current examples of optical disks include compact disk—read only memory (CD-ROM), compact disk—read/write (CD-R/W) and DVD.
The computer usable medium has computer usable program code embodied thereon, the computer usable program code comprising various code operable to control the operation of the system 1. In particular, in a first embodiment, the computer usable program code is operable to enable the computer processor to communicate with one or more differential air pressure sensors and phase sensors, so as to receive and store data therefrom. Further, computer usable program code is operable to enable the control system 33 to synchronize frequency and voltage phase of the synchronous generator 31 with the voltage phase of an external AC power line 61 in communication with the system 1.
In a further preferred embodiment, the computer program of the present invention is further operable to control the electromagnetic brakes 49 to modulate shaft power delivered to the generator(s) units 31 during wind transients and to control the pitch of the adjustable pitch directrix blades 67 to control turbine power and so as to prevent instantaneous overloads of the generator units 31, to control the speed of the generator units 31 during loss of external electrical load of the generator units 31 via application of the electromagnetic brakes 49, to control voltage of the generator units 31 during normal operation and at the moment of loss of external electrical load of the generator units, and to monitor and redirect mechanical loads of greater than 100% of full generator power to the electromagnetic brakes after loss of external electrical load, so as to maintain the turbines at full speed for a short time until the external electrical load is restored, thereby allowing the generator to quickly resume power generation after short load interruptions.
Thus, the computer program product provides the following general functionality:
(1) communication of the computer processor 35 with one or more of the various sensors;
(2) synchronization of the voltage and phase of the generator units 31 with the voltage and phase of an external power line in communication with the system;
(3) control of the 3-phase AC power switch (breaker); and
(4) control of the turbine magnetic brakes so as to control and monitor the speed of rotation and phase of the generator, and the torque applied to the generator.
Further, the computer program is operable to enable the control system 33 to control operation of the turbine magnetic brakes 49 (electromagnetic) and 56 (permanent magnets), and the pitch of the adjustable pitch directrix blading 67 via a servo controller in communication with the computer processor 35 and the adjustable pitch directrix blades 67. In another preferred embodiment, the computer program is also operable to enable the control system 33 to control operation (opening and closing) of the pivotable air bypass doors 53.
Although specific embodiments of the invention have been disclosed, those having ordinary skill in the art will understand that changes can be made to the specific embodiments without departing from the spirit and scope of the invention. The scope of the invention is not to be restricted, therefore, to the specific embodiments. Furthermore, it is intended that the appended claims cover any and all such applications, modifications, and embodiments within the scope of the present invention.
This application is a CIP (continuation-in-part) patent application of copending U.S. patent application Ser. No. 12/888,647, filed Sep. 23, 2010, which is a CIP of copending U.S. patent application Ser. No. 12/713,140, filed Feb. 25, 2010, the contents of both of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12888647 | Sep 2010 | US |
| Child | 13280634 | US | |
| Parent | 12713140 | Feb 2010 | US |
| Child | 12888647 | US |
